Liquid Crystal Display Panel

ABSTRACT

A laminated spacer portion formed by laminating various thin films that constitute thin-film transistors is disposed in peripheral driver circuits. As a result, even in a structure in which part of a sealing member is disposed above the peripheral driver circuits, pressure exerted from spacers in the sealing member is concentrated on the laminated spacer portion, whereby destruction of a thin-film transistor of the peripheral driver circuits can be prevented caused by the pressure from the sealing portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/694,616, filed Jan. 27, 2010, now allowed, which is a continuation ofU.S. application Ser. No. 11/782,042, filed Jul. 24, 2007, now U.S. Pat.No. 7,667,817, which is a continuation of U.S. application Ser. No.09/548,524, filed Apr. 13, 2000, now U.S. Pat. No. 7,298,447, which is acontinuation of U.S. application Ser. No. 08/877,919, filed Jun. 18,1997, now U.S. Pat. No. 6,055,034, which claims the benefit of a foreignpriority application filed in Japan as Serial No. 08-185636 on Jun. 25,1996, all of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits, as well as tovarious apparatuses using such a panel.

2. Description of the Related Art

An active matrix liquid crystal display panel is known in which anactive matrix circuit and peripheral driver circuits for driving it areintegrated on a glass substrate or a quartz substrate. In such an activematrix liquid crystal display panel, various measures have been taken tominimize the area of portions unnecessary for display, i.e., the areaoccupied by the peripheral driver circuits.

On the other hand, in the liquid crystal display panel, a sealing memberis provided in a peripheral portion to hold, i.e., confine a liquidcrystal between a pair of substrates. As one measure to minimize thearea of portions unnecessary for display, it is now required to reducethe area occupied by the sealing member.

The active matrix liquid crystal display panel which is integral withthe peripheral driver circuits has a problem that failures likely occurin the peripheral driver circuits. This tendency is more remarkable in aconfiguration in which part of the sealing member is disposed above theperipheral driver circuits.

This problem occurs in the following manner. The sealing member containsa kind of spacer called a filler to maintain the gap between thesubstrates. In general, the peripheral driver circuits have a very highdegree of integration. In these circumstances, pressure is exerted fromthe filler on thin-film transistors and a wiring of the peripheraldriver circuits which are located right under the filler (the pressureis estimated to be very strong locally), so that a line disconnection, acontact failure, and even a disconnection of a semiconductor layer arelikely to occur.

Although spherical substrate gap holding means called spacers are alsoused in the active matrix area, the occurrence of failures in the activematrix area due to the existence of the spacers is not so serious as inthe peripheral driver circuits, because the degree of integration is lowin the active matrix area.

SUMMARY OF THE INVENTION

An object of the present invention is to minimize the area of portionsother than a pixel matrix circuit in an active matrix liquid crystaldisplay panel which is integral with peripheral driver circuits.

Another object of the invention is to prevent destruction of aperipheral driver circuit due to pressure exerted from a sealing membereven in the active matrix liquid crystal display panel that attains theabove object.

According to a first aspect of the invention, as shown in FIGS. 1A to 1Dand 2 in the form of a specific manufacturing process, there is provideda liquid crystal display panel comprising an active matrix circuit(pixel circuit); a peripheral driver circuit, the active matrix circuitand the peripheral driver circuit being integrated on the same substrate101; a sealing member (indicated by numeral 206 in FIG. 2), part of thesealing member being disposed above the peripheral driver circuit;thin-film transistors formed in the peripheral driver circuit; and aprotrusion (laminated spacer) formed in the peripheral driver circuit,the protrusion being a lamination of materials that constitute thethin-film transistors, the protrusion being projected (see FIG. 1D) fromportions where the thin-film transistors are disposed.

According to a second aspect of the invention, as shown in FIGS. 1A to1D and 2 in the form of a specific manufacturing process, there isprovided a liquid crystal display panel comprising an active matrixcircuit (pixel circuit); a peripheral driver circuit, the active matrixcircuit and the peripheral driver circuit being integrated on the samesubstrate 101; a sealing member (indicated by numeral 206 in FIG. 2),part of the sealing member being disposed above the peripheral drivercircuit; thin-film transistors formed in the peripheral driver circuit;and a protrusion (laminated spacer) formed in the peripheral drivercircuit in addition to the thin-film transistors, the protrusion being alamination of materials that constitute the thin-film transistors, theprotrusion being higher (see FIG. 1D) than portions where the thin-filmtransistors are disposed.

According to a third aspect of the invention, as shown in FIGS. 1A to 1Dand 2 in the form of a specific manufacturing process, there is provideda liquid crystal display panel comprising an active matrix circuit(pixel circuit); a peripheral driver circuit, the active matrix circuitand the peripheral driver circuit being integrated on the same substrate101; a sealing member (indicated by numeral 206 in FIG. 2), part of thesealing member being disposed above the peripheral driver circuit;thin-film transistors formed in the peripheral driver circuit; and aprotrusion formed in the peripheral driver circuit in addition to thethin-film transistors, the protrusion being a lamination of materialsthat constitute the thin-film transistors, the protrusion having afunction of a spacer.

According to a fourth aspect of the invention, as shown in FIGS. 1A to1D and 2 in the form of a specific manufacturing process, there isprovided a liquid crystal display panel comprising an active matrixcircuit (pixel circuit); a peripheral driver circuit, the active matrixcircuit and the peripheral driver circuit being integrated on the samesubstrate 101; a sealing member (indicated by numeral 206 in FIG. 2),part of the sealing member being disposed above the peripheral drivercircuit; thin-film transistors formed in the peripheral driver circuit;and a laminated portion (laminated spacer) formed in the peripheraldriver circuit in addition to the thin-film transistors, the laminatedportion having more laminated layers (see FIG. 1D) than portions wherethe thin-film transistors are disposed in the peripheral driver circuit.

As shown in FIGS. 1A to 1D and 2, the protrusion (laminated spacer) isformed by laminating all the thin films that constitute the pixelcircuit and the peripheral driver circuits, the latter circuits having ahigh degree of integration. With this structure, pressure exerted fromspacers 204 in the sealing member 206 is concentrated on the protrusion.As a result, the thin-film transistors and the wiring of the peripheraldriver circuits can be prevented from being damaged.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1D are sectional views showing a manufacturing process of anactive matrix liquid crystal panel according to Embodiment 1 of thepresent invention;

FIG. 2 is a sectional view showing the active matrix liquid crystalpanel according to Embodiment 1 of the invention; and

FIGS. 3A to 3E show apparatuses to which a liquid crystal display panelof the invention is applied according to Embodiment 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

This embodiment is directed to an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits. FIGS. 1A to 1Dand 2 show its manufacturing process.

This embodiment is directed to manufacture of a liquid crystal displaypanel that is constituted of a pixel circuit (active matrix circuit) andperipheral driver circuits for driving it. For example, the peripheraldriver circuits are composed of a shift register circuit, a buffercircuit, and a sampling circuit.

First, a base film (not shown) is formed on a glass substrate 101.Alternatively, a quartz substrate may be used. In this embodiment, a3,000-Å-thick silicon oxide film is formed by plasma CVD as the basefilm.

A 500-Å-thick amorphous silicon film (not shown) is then formed bylow-pressure thermal CVD.

A crystalline silicon film is obtained by crystallizing the amorphoussilicon film by illuminating it with laser light. Other means may beused to obtain a crystalline silicon film.

The thus-obtained crystalline silicon film is patterned into a pattern102, a pattern indicated by numerals 103 to 105, and a pattern indicatedby numerals 106 to 108. The pattern 102 will become a semiconductorpattern to constitute a laminated spacer 1000. The pattern indicated bynumerals 103 to 105 will become an active layer pattern of a thin-filmtransistor in a peripheral driver circuit 1001. The pattern indicated bynumerals 106 to 108 will become an active layer pattern of a thin-filmtransistor in a pixel circuit (active matrix circuit) 1002.

The laminated spacer is a laminated protrusion of all the componentsthat are formed intentionally in the TFT substrate. If the laminatedspacer is disposed in a peripheral driver circuit, pressure from thespacers for holding the substrate gap is concentrated on the laminatedspacer. As a result, pressure exerted on thin-film transistors and awiring that constitute the peripheral driver circuits can be reduced.

In this embodiment, it is assumed that all the illustrated thin-filmtransistors are of an n-channel type. In general, the peripheral drivercircuits are constituted of n-channel and p-channel thin-filmtransistors. On the other hand, n-channel or p-channel transistors areused in the pixel circuit.

After the patterning of the semiconductor layer, a gate insulating film109 is formed, and then an aluminum film (not shown) for forming gateelectrodes (and gate lines extending therefrom) is formed on the gateinsulating film 109. In this embodiment, a 4,000-Å-thick aluminum filmis formed by sputtering by using an aluminum target containing scandiumat 0.18 wt %.

The thus-formed aluminum film is patterned into aluminum patterns 110 to112. The pattern 110 is an aluminum pattern to constitute the laminatedspacer. The pattern 111 is a gate electrode of the thin-film transistorin the peripheral driver circuit. The pattern 112 is a gate electrode ofthe thin-film transistor in the pixel circuit.

Subsequently, 1,000-Å-thick anodic oxide films 113 to 115 are formed byanodization in which the aluminum patterns 110 to 112 are used as theanodes. Thus, the state of FIG. 1A is obtained.

Silicon nitride films may be used instead of anodic oxide films. As afurther alternative, oxide films (plasma oxide films) may be formed byplasma processing in an oxidizing atmosphere.

In the state of FIG. 1A, a 3,000-Å-thick silicon nitride film as a firstinterlayer insulating film 116 is formed by plasma CVD (see FIG. 1B).

After contact holes are formed, a multilayer metal film in which analuminum film is interposed between titanium films is formed bysputtering.

The three-layer metal film is patterned into a pattern 117, a sourceelectrode 118, a drain electrode 119, a source electrode 120, and adrain electrode 121. The pattern 117 will become part of the laminatedspacer. Thus, the state of FIG. 1B is obtained.

Thereafter, a 15,000-Å-thick resin layer 122, specifically a polyimidelayer, as a second interlayer insulating film is formed by spin coating.The use of the resin layer 122 is advantageous in that its surface canbe made flat.

Subsequently, a 3,000-Å-thick titanium film is formed by sputtering, andthen patterned into a pattern 124 and a pattern 125. The pattern 124 isa titanium film pattern to become part of the laminated spacer. Thepattern 125 is a black matrix (BM), which has a function of shieldingthe thin-film transistors in the pixel circuit from light.

Then, a 3,000-Å-thick resin layer 126, specifically a polyimide layer,as a third interlayer insulating film 126 is formed by spin coating.

After contact holes are formed, a 1,000-Å-thick ITO film is formed overthe entire surface by sputtering. The ITO film is patterned into apattern 127 and an ITO pixel electrode 128. The pixel electrode 128 isin contact with the drain electrode 121. An auxiliary capacitance isformed in a region where the pixel electrode 128 and the black matrix125 coextend. Thus, the state of FIG. 1D is obtained.

The ITO pattern 127 is also left, as a dummy, in the laminated spacerportion. This makes the laminated spacer portion the thickest in theentire substrate structure. That is, the laminated spacer portion isprovided as a protrusion which is wider than a given area and in whichall the components are laminated.

Subsequently, an opposed glass substrate 201 (or a quartz substrate) isprepared as shown in FIG. 2. An opposed electrode 202 and an orientationfilm 203 are formed on the opposed glass substrate 201.

Reference numeral 206 denotes a sealing member, and numerals 204 and 205denote spacers included in the sealing member 206. A liquid crystal 207is sealed within the liquid crystal cell by the sealing member 206.

In the structure shown in FIG. 2, pressure exerted from the spacers 204and 205 is concentrated on the laminated spacer portion. This is becausethe laminated spacer portion is a highest protrusion having a certainarea.

The coextending portion of the black matrix 125 and the pixel electrode128 in the pixel circuit is equal in height (i.e., thickness) to thelaminated spacer portion. However, since the coextending portion hasonly a small area and the degree of integration is low in the pixelcircuit, the occurrence of wiring disconnections and TFT failures due topressure exerted from the spacer 208 is negligible.

The structure of FIG. 2 is particularly advantageous in that linedisconnections and operation failures of TFTs can be prevented in theperipheral driver circuit regions where the degree of integration ishigh.

As described above, by providing the laminated spacer in the activematrix liquid crystal display panel which is integral with theperipheral driver circuits, the peripheral driver circuits can beprevented from being damaged by pressure exerted from spacers that areincluded in the sealing member even if part of the sealing member isdisposed above the peripheral driver circuits.

Embodiment 2

This embodiment is directed to a case where the invention is applied toa configuration in which not only the peripheral driver circuits butalso various processing circuits and memory circuits are integrated onthe same substrate.

The structure called “system on panel” has been proposed as an advancedversion of the liquid crystal display panel which is integral with theperipheral driver circuits. In this new structure, various processingcircuits and memory circuits as well as the active matrix circuit andthe peripheral driver circuits are integrated on the same substrate.This structure is intended to reduce the size of an informationprocessing terminal by integrating its functions on a single glasssubstrate.

Also in this structure, it is required to reduce the area of theportions other than the pixel circuit (active matrix circuit). Thisnecessarily requires a structure in which the sealing member isoverlapped with various integrated circuits which constitute variousprocessing circuits and memory circuits.

To satisfy this requirement, the laminated spacer as described in thefirst embodiment may be provided in such integrated circuits, wherebythe integrated circuits constituting various processing circuits andmemory circuits which are high in the degree of integration can beprevented from being damaged by pressure exerted from spacers in thesealing member.

Embodiment 3

An active matrix liquid crystal display panel which is integral withperipheral driver circuits according to the invention can beincorporated in various apparatuses.

The use of the invention in an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits is veryadvantageous because in such a panel the peripheral driver circuits arerequired to have a high degree of integration.

FIG. 3A shows a digital still camera, an electronic camera, or animaging apparatus called “video movie” which can deal with motionpictures.

This apparatus has a function of electronically storing pictures takenby a CCD camera (or some other proper imaging means) that isincorporated in a camera section 2002. The apparatus also has a functionof displaying a picture thus taken on a liquid crystal display panel2003 that is incorporated in a main body 2001. The apparatus is operatedby using operation buttons 2004.

By applying the invention to this apparatus, the non-display area of theliquid crystal display panel 2003 can be minimized, which enablesminiaturization of the apparatus.

FIG. 3B shows a portable personal computer (information processingapparatus). Provided with a liquid crystal display panel 2104 in a cover2102 that is attached to a main body 2101 and possible to open andclose, this apparatus allows a user to input various information orperform operations for various computations through a keyboard 2103.

FIG. 3C shows a case where a flat panel display is used in a carnavigation system (information processing apparatus). The car navigationsystem consists of an antenna section 2304 and main body 2301 thatincorporates a liquid crystal display panel 2302.

Switching among various pieces of information needed for navigation isperformed by operation buttons 2303. A remote controller (not shown) iscommonly used for various operations.

FIG. 3D shows an example of a projection image display apparatus. Asshown in FIG. 3D, light emitted from a light source 2402, formed in amain body 2401, optically modulated into an image by a liquid crystaldisplay panel 2403. The image is reflected projected onto a screen 2406after being reflected by mirrors 2404 and 2405.

FIG. 3E shows an example in which a main body 2501 of a video camera(imaging apparatus) is provided with a display device called a viewfinder.

The view finder is generally composed of a liquid crystal display panel2502 and an eyepiece unit 2503 which displays an image.

The video camera of FIG. 3E is operated by using operation buttons 2504,and pictures are recorded on a magnetic tape that is accommodated in atape holder 2505. Pictures taken by a camera (not shown) is displayed onthe liquid crystal display panel 2502. Pictures recorded on the magnetictape are displayed on the display panel 2502.

In the video camera of FIG. 3E, it is required to minimize the area ofthe portions of the liquid crystal display panel 2502 other than thedisplay region (pixel region). Therefore, the employment of theconfiguration as described in the first embodiment is very advantageous.

As described above, the area of the portions other than the pixel matrixcircuit can be minimized in an active matrix liquid crystal displaypanel which is integral with peripheral driver circuits.

It becomes possible to prevent destruction of a peripheral drivercircuit due to pressure exerted from the sealing member even in theactive matrix liquid crystal display panel in which the area of thenon-display portions is minimized.

1. A display device comprising: an active matrix circuit over a firstregion of a substrate, the active matrix circuit including at least onetransistor, the at least one transistor including a gate electrode, asemiconductor layer, and a gate insulating film interposed between thegate electrode and the semiconductor layer; a conductive layerelectrically connected to the semiconductor layer; a pixel electrodeelectrically connected to the conductive layer; a laminated layer over asecond region of the substrate; a sealing member over the laminatedlayer, wherein the laminated layer includes a first layer containing asame material as the gate electrode, and a second layer containing asame material as the semiconductor layer, and a third layer containing asame material as the conductive layer, and wherein the laminated layerdoes not function as a transistor.
 2. The display device according toclaim 1, wherein at least one spacer is included in the sealing member.3. The display device according to claim 1, wherein the gate electrodeis formed over the semiconductor layer.
 4. The display device accordingto claim 1, wherein the conductive layer is a laminated structure oftitanium and aluminum.
 5. The display device according to claim 1,wherein the semiconductor layer includes crystalline silicon.
 6. Thedisplay device according to claim 1, wherein the display device isincorporated in one selected from the group consisting of a camera, avideo movie, a personal computer, a car navigation system, and aprojection image display apparatus.
 7. A display device comprising: anactive matrix circuit over a first region of a substrate, the activematrix circuit including at least one transistor, the at least onetransistor including a gate electrode, a semiconductor layer, and a gateinsulating film interposed between the gate electrode and thesemiconductor layer; a conductive layer electrically connected to thesemiconductor layer; a pixel electrode electrically connected to theconductive layer; a laminated layer over a second region of thesubstrate; a sealing member over the laminated layer, wherein thelaminated layer includes a first layer containing a same material as thegate electrode, and a second layer containing a same material as thesemiconductor layer, and a third layer containing a same material as thegate insulating film, and wherein the laminated layer does not functionas a transistor.
 8. The display device according to claim 7, wherein atleast one spacer is included in the sealing member.
 9. The displaydevice according to claim 7, wherein the gate electrode is formed overthe semiconductor layer.
 10. The display device according to claim 7,wherein the conductive layer is a laminated structure of titanium andaluminum.
 11. The display device according to claim 7, wherein thesemiconductor layer includes crystalline silicon.
 12. The display deviceaccording to claim 7, wherein the display device is incorporated in oneselected from the group consisting of a camera, a video movie, apersonal computer, a car navigation system, and a projection imagedisplay apparatus.